chore: bump upload-artifact to v4

Author: jurevans

.github/workflows/build-extension-demo.yml

@@ -62,7 +62,7 @@ jobs:
           SHA: ${{ github.sha }}
         run: NAMADA_INTERFACE_REVISION=$SHA yarn build:chrome
 
-      - uses: actions/upload-artifact@v3
+      - uses: actions/upload-artifact@v4
         with:
           name: namada-keychain-chrome
           path: ./apps/extension/build/chrome/namada_keychain-*.zip
@@ -97,7 +97,7 @@ jobs:
           SHA: ${{ github.sha }}
         run: NAMADA_INTERFACE_REVISION=$SHA yarn build:firefox
 
-      - uses: actions/upload-artifact@v3
+      - uses: actions/upload-artifact@v4
         with:
           name: namada-keychain-firefox
           path: ./apps/extension/build/firefox/namada_keychain-*.zip